18506905 has 4 divisors (see below), whose sum is σ = 22208292. Its totient is φ = 14805520.

The previous prime is 18506903. The next prime is 18506933. The reversal of 18506905 is 50960581.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2274064 + 16232841 = 1508^2 + 4029^2 .

It is not a de Polignac number, because 18506905 - 2¹ = 18506903 is a prime.

It is a super-3 number, since 3×18506905³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18506903) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1850686 + ... + 1850695.

It is an arithmetic number, because the mean of its divisors is an integer number (5552073).

Almost surely, 2^18506905 is an apocalyptic number.

It is an amenable number.

18506905 is a deficient number, since it is larger than the sum of its proper divisors (3701387).

18506905 is an equidigital number, since it uses as much as digits as its factorization.

18506905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3701386.

The product of its (nonzero) digits is 10800, while the sum is 34.

The square root of 18506905 is about 4301.9652485812. The cubic root of 18506905 is about 264.5115244948.

The spelling of 18506905 in words is "eighteen million, five hundred six thousand, nine hundred five".